North Korea is estimated to have between 20 and 60 nuclear bombs, as well as the capacity to produce six new ones every year, the US Army said in its latest report, adding that the communist country pursues its nuclear weapons program to prevent a forcible regime change from outside.

“External powers intervened in Libya when the domestic revolts began in 2011. The Kim family does not want something similar to happen in North Korea,” said the report, titled “North Korean Tactics.”

It said the North is also the third-largest holder of chemical agents in the world, potentially maintaining a 2,500- to 5,000-ton stockpile of 20 chemical weapons.

“North Korea possibly has weaponized anthrax or smallpox that could be mounted on missiles for use,” the report said, adding that 1 kilogram of anthrax could kill up to 50,000 people in the 10-million-strong South Korean capital, Seoul.

North Korea, however, has an incomplete record of missile accuracy -- attributable to insufficient crew training and frequent ammunition failure -- so its missile operations focus on high-priority targets.

But nuclear and chemical weapons would not have to be accurate to be effective because of the panic such attacks would cause and their aftereffects, according to the report.

In addition to conventional weapons, the report said the North continues to oversee electronic warfare operations, with over 6,000 computer hackers working overseas to gather intelligence, disable enemy networks and commit financial crimes.

Those hackers, reporting to Pyongyang’s cyberwarfare agency or Bureau 121, operate in countries such as China, Russia, Malaysia, India and Belarus. The bureau includes the infamous Lazarus Group, which infiltrated South Korean financial and media networks in March 2013 and a year later hacked into Sony Pictures.

The report said military networks might be susceptible to a breach by Pyongyang, with some experts warning Seoul to take precautions.

Bruce Bennett, a senior defense analyst at RAND Corp., told Radio Free Asia that the North could penetrate into South Korea’s military radar in the event of a conflict, rendering any immediate counterattack ineffective.

The report concluded that the North would fight a two-front war with the South. A massive conventional assault across the inter-Korean border, along with chemical and biological weapons, would follow, with an intercontinental ballistic missile aimed at US targets in Hawaii, Alaska or even the California coast.

The second front would involve sending special forces to the South’s southern regions and having them join forces with clandestine operatives already there.

Since Pyongyang would have to offset deficiencies in firepower to counter the Seoul-Washington alliance during an armed conflict, it would rely on “asymmetric warfare” to make up for what it lacks in terms of the latest technologically advanced equipment, the report said.

By Choi Si-young (siyoungchoi@heraldcorp.com)